The proposed research involves exploration of the hypothesis that Phaseolus vulgaris tissues suppress toxin synthesis of Pseudomonas phaseolicola, and that this is the basis of resistance of host tissues. Objectives involve the determination of structure of the toxin by means of NMR, gas chromatography and mass spectrometry. Hydrolysates of the toxin would be TAB derivatized to obtain initial separation of the components. Toxin synthesis would be studied in the cell-free systems to determine how the toxin molecule is synthesized. In culture the effect of various compounds on the synthesis of toxin by the pathogen would be studied. Phaseolus (sp.) tissues would be examined for compounds which have the ability to induce or repress toxin synthesis.